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Discussion Starter #1
When I was going home, I notice the front left wheel dropped to 31 PSI. This is when I thought I had a puncture or a nail in the tire. I inspected it when I got home and found the tire to be perfect.

This is when I decided to just put some air into it with my VIAIR Air Compressor to be safe. This is when I noticed something strange... My VIAIR Air Compressor gauge said that tire's PSI is 39-40.

My TPMS says 37-39 PSI for the other 3 wheels but only the front left says 31 PSI. The other 3 wheels makes sense because I know my friend (who installed my wheels/tires) set my PSI to around 37ish.

Could the TPMS sensor in the front left wheel be glitching and not reading the tire pressure in that tire properly? Is there a way to reset this? I tried searching this form but I couldn't find instructions to how to reset the TPMS.
 

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TPMS sensors are not precision devices. Having said that mine jive with my pretty accurate gage and with each other. My wife's Merc has one lazy one. It always reads 1-2 PSI low. It's just how they are. They are not intended to replace a good gage but rather as a rough motoring tool.

As I drive they can vary slightly based on different factors which will make the tires heat up at slightly different rates.
 
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That sensor COULD be low battery/ time for a swap? Mine are pretty accurate to what the gauge says. Although my RH Front tire always remains the same when driving vs the other 3 that heat up and go up 1-2 PSI and my OCD drives me nuts
 

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My TPMS sensors are right on the money and my tire pressures will go up a few PSI after driving for a while. Still, I don't trust their accuracy and check my tires with a quality tire pressure gauge when cold.
 

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Mine are spot on accurate when compared to my Longacre digital tire gauge.
 
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Discussion Starter #6
Thanks for the reply all!

I know the TPMS gauge is not always accurate. I know that some car brands are more accurate than others. And I know even within a car brand, not all cars have the TPMS that is accurate. My Acura before my Infiniti had a pretty accurate TPMS.

That sensor COULD be low battery/ time for a swap? Mine are pretty accurate to what the gauge says. Although my RH Front tire always remains the same when driving vs the other 3 that heat up and go up 1-2 PSI and my OCD drives me nuts
Low battery already? Dang. The car is coming up to 3 years old (bought in late 2017); I didn't think the TPMS battery sensor battery would go bad that fast. My previous car, the Acura, had TPMS sensors working properly for hella long. The car was 11 years old before I gave it up and the TPMS sensors were fine.
 

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Discussion Starter #7
TPMS sensors are not precision devices. Having said that mine jive with my pretty accurate gage and with each other. My wife's Merc has one lazy one. It always reads 1-2 PSI low. It's just how they are. They are not intended to replace a good gage but rather as a rough motoring tool.

As I drive they can vary slightly based on different factors which will make the tires heat up at slightly different rates.
Yeah. I'm okay with like 1-2 PSI margin of error. But its strange that is about 7-9 PSI difference from what it really is.
 

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That is too much variation for sure.
 

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mine are just about dead on as well.

Did you try a different gauge?
 

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Discussion Starter #10
mine are just about dead on as well.

Did you try a different gauge?
Yeah. I used to my VIAIR air compressor's gauge. I obviously trust the compressor's gauge more than the TMPS because tech tends to glitch, which is why I'm so confused.

What do you mean your TPMS is about dead too? Isn't your vehicle like 2018?

What happens when the TPMS is about dead? Is your TPMS reading wrong PSI numbers as well? Does a "!" check tire warning show up?
 

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Did you try a different gauge?
I believe jodedor is asking if you used a standalone gauge. I personally trust the TPMS more than the gauge on my compressor. However, the TPMS matches up with my old school tire pressure gauge pretty well. In your case, it may be worthwhile to get a standalone pressure gauge to verify. They're pretty cheap. If 2 of the 3 match, you know which one is wrong.
 

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Discussion Starter #12
I believe jodedor is asking if you used a standalone gauge. I personally trust the TPMS more than the gauge on my compressor. However, the TPMS matches up with my old school tire pressure gauge pretty well. In your case, it may be worthwhile to get a standalone pressure gauge to verify. They're pretty cheap. If 2 of the 3 match, you know which one is wrong.
Ahh. Well - I did use my VIAIR air compressor gauge on all 4 of my wheels. Everyone matched up to the PSI the TPMS was showing except for the front left.

I do have a standalone gauge coming from Amazon this Saturday. I ordered myself that RHINO air pressure gauge. I heard its pretty good and it was like $18 dollars. I bought it just to have and to use to double check the wheels again too. But I'm like 99% sure my VIAIR air compressor gauge is accurate since the other 3 wheels matched up with the TPMS.

This is why I'm assuming the front left is either glitching or faulty. I don't know which yet. I'm trying to see if anyone knows how to reset it.
 
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I think you need a scan tool to reset, not 100% positive on that.
 

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Discussion Starter #14
I think you need a scan tool to reset, not 100% positive on that.
Ahhh. Dang. Really? I thought you could it without any tools.
 

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Yeah. I used to my VIAIR air compressor's gauge. I obviously trust the compressor's gauge more than the TMPS because tech tends to glitch, which is why I'm so confused.

What do you mean your TPMS is about dead too? Isn't your vehicle like 2018?

What happens when the TPMS is about dead? Is your TPMS reading wrong PSI numbers as well? Does a "!" check tire warning show up?
That's a good question. I don't see any reference in the manuals about a low TPMS battery warning. I think the information display will just show dashed lines for the tire if its TPMS sensor stops functioning.
 
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Discussion Starter #16
That's a good question. I don't see any reference in the manuals about a low TPMS battery warning. I think the information display will just show dashed lines for the tire if its TPMS sensor stops functioning.
Thanks for the reply.

Hmmm. I don't see any dashed lines for the tire. I'm assuming my TPMS for the front left wheel is still working but its reading way below what it actually says.

My worry is that it'll keep reading low. Or glitch to a point where it reads under 25 PSI but realistically its not under 25 PSI.
 

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Thanks for the reply.

Hmmm. I don't see any dashed lines for the tire. I'm assuming my TPMS for the front left wheel is still working but its reading way below what it actually says.

My worry is that it'll keep reading low. Or glitch to a point where it reads under 25 PSI but realistically its not under 25 PSI.
TPMS sensors can go bad. If you have tire pressure showing on the information display for a tire, yet the pressure indication is way off from a gauge reading, I'd suspect the TPMS sensor needs to be replaced. If you go that route, make sure the replacement is 433 MHz.
 
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Discussion Starter #18
TPMS sensors can go bad. If you have tire pressure showing on the information display for a tire, yet the pressure indication is way off from a gauge reading, I'd suspect the TPMS sensor needs to be replaced. If you go that route, make sure the replacement is 433 MHz.
Is the 433Mhz the OEM Mhz?

If I don't replace it, do you think it'll get to a point where the TPMS will say I have a low pressure tire when in fact I don't? My worry is that it'll pop out a tire pressure warning light but the tire pressure isn't actually low.

I can probably just ignore the low PSI in one wheel, but saying I have a low pressure tire with a warning but when I don't would be annoying.
 

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Is the 433Mhz the OEM Mhz?

If I don't replace it, do you think it'll get to a point where the TPMS will say I have a low pressure tire when in fact I don't? My worry is that it'll pop out a tire pressure warning light but the tire pressure isn't actually low.

I can probably just ignore the low PSI in one wheel, but saying I have a low pressure tire with a warning but when I don't would be annoying.
OEM is 433 MHz. That TPMS could give you a low tire pressure warning light if it thinks the tire pressure is below 25 PSI (not sure of that pressure) regardless of the actual tire pressure. My OCD couldn't stand to have one TPMS sensor bad and I'd have to replace it.

BTW, why are you running your tire pressures above the recommended 35 PSI cold?
 

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Discussion Starter #20
OEM is 433 MHz. That TPMS could give you a low tire pressure warning light if it thinks the tire pressure is below 25 PSI (not sure of that pressure) regardless of the actual tire pressure. My OCD couldn't stand to have one TPMS sensor bad and I'd have to replace it.

BTW, why are you running your tire pressures above the recommended 35 PSI cold?
That's my main worry. I don't want it throwing a tire pressure light if it gets to that point. If it doesn't but its still faulty, I can ignore it.

I'm actually not. The cold/non-driven PSI on the car is 34-36 PSI. The 37-39 PSI that was shown yesterday is a result of me driving home for about 30 minutes and it was a rather hot day too..
 
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